Yay! I fixed it!
I was about to give up, had both units, the one I've had since Jan. 2, 2000 (that works) and the non-working one, side by side on my outdoors patio table in the sun, covers off.
I combed the service manual, got a chocolate fix, a cup of coffee.
I had determined where the gears are that run the carousel. Everything looked the same in both units. A 1/2 hour ago or so I discovered that I could turn the carousel in the good one by hand, which turned the gears. Something was preventing the carousel in the other one from turning. It was just jammed tight. I had my every-day-carry mini-flashlight on the highest setting looking everywhere. Finally I determined that something was catching the carousel, keeping it from turning. I'd shaken the unit, turned it upside down, nothing seemed loose in there. Then, 5 minutes ago, I detect that something was jammed into the carousel from the perimeter, almost as if it were designed to do so. I hadn't been able to find anything for "lock" in the service manual, i.e. a mechanism to lock the carousel into place. However, a poke with a long thin screwdriver got the offending gizmo to snap back into place away from the carousel, it appears to work now!!!
I did not expect to be able to fix this thing. I'll make sure it's working before sending the good news to the seller. His response today was to gladly accept the return. I'm going to test it now with some disks, play some music :whiste:
Funny, there's a slight difference between these. The one I bought Jan. 2, 2000 has a front panel jog wheel that's relatively stiff, far stiffer than the one I got from this guy in Florida. Mine rotates the carousel when the door isn't open, his doesn't. Not important differences, I figured maybe firmware on the non-rotation with door closed thing. Otherwise I see absolutely no difference between the two machines. Both say on the back that they were manufactured in September 1998.